Continuity mistake: While Eddie and his girl are talking on the sidewalk after she was fired, a lady in a brown coat passes behind them at least three different times.
Continuity mistake: While Eddie is talking with Anne and her new boyfriend, she has a purse which disappears and reappears between shots.
Continuity mistake: When Eddie and Anne are on their date night Eddie starts laughing, we then cut to a view over his left shoulder and he's instantly not laughing or smiling.
Other mistake: When Maria dies after infecting Eddie with the symbiote her head's turned to her right. A shot of Eddie then her again, suddenly her head's turned towards Eddie who's on her left on the floor.
Continuity mistake: After Venom is separated from Eddie he escapes by the air vent, and in the wide view a monitor disappears between shots.
Continuity mistake: The girl that got the riot symbiote from Jameson has plastic gloves before she leaves the ambulance but when she is outside they are gone.
Continuity mistake: When Eddie is looking for a job, he marks on the newspaper with a pen on the right side but in the next shot it's on the left.
Continuity mistake: The body of the homeless guy changes after the symbiote leaves his body.
Continuity mistake: The Ducati Scrambler doesn't have a mirror in the first scene, but during the car chase there is one suddenly on its left side.
Continuity mistake: At the end when Anne and Eddie are sitting on the step talking we can see a man in the background walking towards them wearing a light grey/blue top. As the camera cuts to Anne and then Eddie the man disappears, he doesn't pass them as other people do and he doesn't cross the road.
Revealing mistake: After the spaceship crashes to the Earth, the ambulance rushes the wounded astronauts to the hospital. On the way, a symbiote takes control of one man, and kills the emergency vehicle's driver, causing the van to wreck. The final shot of this wreck when the ambulance takes the last roll and stops on its side, shows the CGI involved with the unnatural movement of the van. (00:03:50)
Answer: Venom was using Eddie, much like Riot, to invade Earth. Venom was damaging Eddie's body until he grew to like him, which is why he said he could fix it while Dan was telling Eddie all of this.